I have a SST on route and the operator called me to inform me that the high scores had all reset to default. So, I went in to check it out.
1. I had swapped out the offboard batteries in January. They are still in place and look good.
2. I unplugged the game and rebooted. The scores that are in there now stayed in place.
3. My previous custom message that has always been there is still in place.
4. The auto high score reset (setting 27 I believe) is set to 2000 (the default). There are about 1675 plays showing in audits.

So, that leads me to believe that no factory reset has taken place, since my other settings are there (custom message).
The game plays fine and I keep the key. So, no one has gotten inside and reset anything.
I set the auto high score reset to off while I was there today.

Does anyone have any idea what might have caused this. Scratching my head on this and lamenting the loss of my GC score!